Landrieu was among the last two Democrats to agree to vote with the rest of their party Saturday to proceed with debate on a Senate version of the bill. Republicans in the Senate wanted to kill the bill by blocking debate. Debate will begin when the Senate returns after Thanksgiving.

Both Cao and Landrieu have concerns that ultimately could lead Landrieu to vote against the final reform package and could lead Cao to vote against the bill if it returns to the House after a Senate-House conference committee.

But DeParle said she believes that Congress can craft legislation that will pass both Houses with both Cao and Landrieu on board.

"I'm very optimistic,'' said DeParle, whose title is director of the White House Office for Health Reform. "For one thing, both of these two people have been incredibly constructive in this debate, and they have not been drive-by folks around health care.''

"With respect to Congressman Cao, I spent hours with him starting back in July and August,'' she said. "When everybody else was on recess, I didn't take a vacation, and he must not have because we had a three-hour phone call from when he was down in New Orleans to talk different aspects of the bill.''

"It's true that he raised the choice and abortion issue every time'' and that he wanted language in the bill that had the blessing of the Catholic bishops, she said. But their discussions focused on broader issues -- "how would small business be affected, how many people in New Orleans would be helped,'' she said.

DeParle said she's known Landrieu for a long time. She says she is friends with her sister, Madeleine, and "we're all former Delta Gammas.''

"Starting back in March, I have been talking to her about small business, about what's the most effective way to contain costs,'' DeParle said.

And all along, she said, Landrieu has expressed "real concerns'' about any public plan.

"These are important questions that should be debated,'' DeParle said. "Is there the ability for a government-sponsored insurance plan to play fairly in the marketplace? Are we solving the problems that are there without creating more problems? Those are all questions of judgment and balance that she has brought to bear on this debate.'' At the same time, DeParle said, "there are many markets, including some in Louisiana, where there really isn't any competition and where coverage isn't affordable.''

"The issues is, should there be another kind of hammer for the insurance industry out there,'' to force them to keep costs down, DeParle said.

In her floor speech Saturday, Landrieu said that while she opposed a public option, "I have suggested that a free-standing, premium-supported, competitive community option that would trigger on a certain date, if our private market reforms fail to work, might be a possible compromise.''

DeParle noted that Landrieu, along with some diehard supporters of a public option, have been charged by Senate Majority Leader Harry Reid, D-Nev., with coming up with a compromise.

"She's one of the people the leader has asked to be engaged in trying to solve it,'' DeParle said. "I think he thinks if I can get something that both Chuck Schumer (D-N.Y.) and Sherrod Brown (D-Ohio) and Mary Landrieu can all support, then I've found the sweet spot."

And DeParle said, "I can see how it would happen. I can see the pieces of an idea out there.''